The present invention relates to an insulator having a laminated core, and particularly to means for mounting a fixing cap onto the core.
Such an insulator comprises both an elongate core including at least one rod made of agglomerated fibers and fixing caps, each of which has a recess in which one of the end core is fixed by an embedding substance. Between the caps, the rod is protected by a covering such as a sheath of insulating substance and may optionally be provided with fins.
An insulator of this type is designed to transmit high mechanical forces and with this aim in view, published French patent specification No. 2,345,796 and No. 2,360,968 in particular describe the use of a recess of a particularly advantageous shape; said recess is shaped like two truncated cones or, more precisely, is flared on either side of an intermediate zone. Thus, when the insulator is subjected to a high traction force, the core with its associated embedding substance tends to slip in the recess of the cap, giving rise to radial compression forces on the rod which cause it to be trapped in the cap.
However, to obtain this result, it is essential for the cap recess to be the right shape and for its surface to be free from rough parts, and therefore careful machining and finishing are usually necessary.
The present invention aims to mitigate this drawback and to allow end caps to be used whose shape and surface condition are not subject to special requirements and which can be obtained, e.g., by casting and used practically in the rough condition in which they leave the foundry.